@fontSize:font-size;
@center:text-align;
@color:color;
@left:left;
@top:top;
@right:right;
@bottom:bottom;
@textAlign:text-algin;
.clear:after{
    display:block;
    clear:both;
    content:"";
}
.left{
    float:left;
}
.rigth{
    float:right;
}
header{
     width:100%;
    max-width: 640px;
    height:0.128rem;
    background:#1448AE;
    line-height:128px;
    @{color}:#fff;
    position:relative;
   
    margin:0 auto;
 
     
}
header .black{
    width:40px;
    height:40px;
    display:inline-block;
  
    position:absolute;
    left:0.21rem;
    top:50%;
    transform:translate(0,-50%);
    background:url("../../images/icon/back.png")0px 0px no-repeat;
    background-size:100% 100%;
}
header span{
   position:absolute;
   @{left}:50%;
   transform:translate(-50%,0);
   @{fontSize}:0.16rem;
   letter-spacing:0.051rem;
}